The broad field of molecular electronics was introduced in the 1970s by Aviram and Ratner. Molecular electronics achieves the ultimate scaling down of electrical circuits by using single molecules as circuit components. Molecular circuits comprising single molecule components can function diversely as switches, rectifiers, actuators and sensors, depending on the nature of the molecule. Of particular interest is the application of such circuits as sensors, where molecular interactions provide a basis for single molecule sensing. In particular, informative current changes could include an increase, a decrease, a pulse, or other time variation in the current.
Notwithstanding the achievements in the field of molecular electronics, new molecular circuits that can function as molecular sensors are still needed. In particular, the need still exists for improved single molecule systems that can yield molecular information with greater signal-to-noise ratios such that signals truly indicative of molecular interactions are distinguishable from non-informative noise.